3. Java- Deploy HTTP Client

Make sure that you still have the Python Flask server from the Python Lab running. If you accidentally shut it down follow steps from the Python lab to restart the Python Flask server.

Start in the Java example directory

Open a new terminal window

cd ~/otelworkshop/host/java

Download Otel Java Instrumentation

Download Splunk OpenTelemetry Java Auto-instrumentation to /opt:

source install-java-otel.sh

Run the Java HTTP requests client

Run the Java client example which uses OKHTTP requests to the Python Flask Server:

Important

If you are doing this workshop as part of a group, before the next step, add your initials do the APM environment: edit the run-client.sh script below and add your initials to the environment i.e. change:
export OTEL_RESOURCE_ATTRIBUTES=deployment.environment=apm-workshop
to
export OTEL_RESOURCE_ATTRIBUTES=deployment.environment=sjl-apm-workshop

source run-client.sh

You will see requests printed to the terminal.

APM Dashboard

Traces/services will now be viewable in the APM dashboard. A new service takes about 90 seconds to register for the first time, the Python and n all data will be available in real time.

Additionally the requests made by Java will print in the terminal where flask-server.py is running. You can use Ctrl+C to stop the requests and server any time.

You should now see a new Java requests service alongside the Python one.

Where is the OpenTelemetry Instrumentation?

In the run-client.sh script the java command:

java \
-Dexec.executable="java" \
-Dotel.resource.attributes=service.name=java-otel-client,deployment.environment=apm-workshop \
-javaagent:/opt/splunk-otel-javaagent.jar \
-jar ./target/java-app-1.0-SNAPSHOT.jar

The splunk-otel-javaagent.jar file is the automatic OpenTelemetry instrumentation that will emit spans from the app. No code changes are necessary! The otel. resources set up the service name Aand environment. Config details can be found here

Splunk's OpenTelmetry autoinstrumentation for Java is here